1. Field of the Invention
The present invention relates to image processing technique for dividing one image into a plurality of areas, executing image processing on a per-area basis, and compositing the areas into one image again.
2. Description of the Related Art
In recent years, advancement in image analysis technique has allowed identifying each individual subject in an image. As stated in Japanese Patent Laid-Open No. 2009-050035, this technique makes it possible to execute high-quality image processing on each individual subject area.
This technique also makes it possible to determine a scene for each of the divided areas obtained by dividing an image into a plurality of areas, instead of determining a subject on a per-pixel basis, and to change image processing for each divided area. As such, there is a conventionally known image processing method for dividing one image, executing image processing on a per-area basis, and compositing the areas into one image again.
In addition, there is a conventionally known method for executing image processing not only based on image information obtained from an image targeted for the image processing, but also based on focus measurement information obtained from a focus measurement sensor. In Japanese Patent Laid-Open No. 2003-087545, a pseudo-defocused image is generated by executing image processing on each of areas obtained by dividing an image using a result of image analysis and defocus information.
As such, there is a conventionally known image processing method for dividing one image, executing image processing on a per-area basis, and compositing the areas into one image again.
When image processing is executed on a per-area basis as has been described above, it is possible to obtain a higher quality image and to be able to blur background areas more easily than when the image processing is executed on the entirety of the image. However, when image processing is executed on a per-area basis, there are always area boundaries, and discontinuity thereof may inhibit the effects of high-quality image processing and pseudo-defocus.
Furthermore, it is rare that only one subject is shown in one picture. In many cases, one picture shows a plurality of subjects, namely scenes corresponding to areas. In such cases, it is necessary to composite the scenes so they look natural.
Furthermore, in photographic presentation, a user's intentions, such as a depth of field and composition, should be reflected in a composite image.